In fighting games there are 2 different terms used when referring to a player’s response to an action: reads and reactions. Both are integral skills to have in order to counter an enemy’s attacks.
A read, to simply put, is an educated guess on what your opponent is going to do next and countering it. In order to read your opponent, you must understand your opponent’s playstyle and habits. Paying close attention to your opponent’s actions throughout the match and their tendencies will allow you to better predict what they might do next in any given situation.
For example, if your opponent is using Jacqui Briggs they might throw out her Bionic Dash move, which is a forward-advancing high attack and is safe on block. In order to punish this move, you must duck underneath it then use a jab or uppercut. Since this move is very quick, it cannot be ducked on reaction and must be done on a read. If you are playing as Noob Saibot, you may notice that your opponent likes to use Bionic Dash after blocking a Spirit Ball. Because you know your opponent’s tendency to use Bionic Dash after every Spirit Ball, the read here would be to duck the next time your Spirit Ball is blocked.
Another example involves Erron Black and his Rattle Snake Slide move. Rattle Snake Slide is a quick, forward-advancing low attack that is -15 on block. You may notice that your opponent always walks back at the start of the match. If you read that your opponent will start to walk back, you can throw out Rattle Snake Slide at the beginning of the match as a counter. Since your opponent is walking backwards and not blocking low, the Rattle Snake Slide will hit. This is known as a hard read. A hard read is a read that has an extremely high risk while yielding very little reward.
Reactions are different from reads in that you are not making an educated guess, but instead reacting to your opponent in a certain situation. Reacting is done by waiting for your opponent to use a specific move and performing an action in response to that move. The average start-up of a move that can be reacted to is roughly 16 frames (though this number may vary depending on the player). This means that any attack that has a start-up of 16 frames or greater can be reacted to.
For example, if your opponent is using Jade they might use her +, which is a slow 28 frame overhead, and mix it up with her Edenian Spark, which is a 20 frame low projectile. The start-up of Jade’s + is much greater than 16 frames, meaning it can be blocked high on reaction. In Mortal Kombat 11, most overheads are slow on start-up and can be reacted to, so it’s usually best to block low in case the opponent uses a low attack then block high on reaction to the overhead.
Keep in mind that if you are focused on reacting to a specific attack, you will be vulnerable to other forms of offense such as jump attacks and throws. Reacting to a single move becomes much more difficult if your opponent adds in other attacks. In order to properly defend against your opponent, you will want to use a combination of both reads and reactions. By successfully reading an opponent, you will be able to better predict their next attack and react accordingly.